(1) Field of the Invention
The present invention relates to wires for liquid crystal displays (LCDs), LCDs having the same and manufacturing methods thereof.
(2) Description of the Related Art
In general, an LCD has a gate wire on a substrate, and the gate wire includes gate lines, gate pads and gate electrodes which transmits scanning signals. The gate wire is covered with a gate insulating layer, and a semiconductor layer is formed on portions of the gate insulating layer opposite is the gate electrodes. The LCD also has a data wire on the gate insulating layer, and the data wire includes data lines, data pads and source electrodes transmitting image signals and drain electrodes connected to the source electrodes through the semiconductor layer. A passivation layer having a contact hole exposing the drain electrode is formed on the data wire, and pixel electrodes which are formed of a transparent conductive material such as ITO (indium tin oxide) and connected to the drain electrodes through the contact hole are formed thereon.
To manufacture the liquid crystal display, deposition, photolithography and etch steps are required to form the gate wire, the data wire, the gate insulating layer, the passivation layer and the pixel electrodes.
There are two general methods for depositing a thin film, a chemical vapor deposition (CVD) and a physical deposition. The CVD forms the film by the reaction of vaporized chemicals that contain the required constituents, while a sputtering which is a kind of physical deposition obtains the film by having energetic particles to strike target to be sputtered physically. The CVD is generally used to form the semiconductor layer and insulating layers such as the gate insulating layer and the passivation layer, and the sputtering is used to form metal layers for the gate wire and the data wire and an ITO layer for the pixel electrodes.
The etch method is divided into two types, wet etch using etchants and dry etch using etching gases.
In particular, when an ITO layer is etched by using an etchant, hydrochloric acid and nitric acid are used. However, it may happen that the etchant penetrates the passivation layer, contacts the data wire and the gate pad, and then erode the data wire and the gate pad. Accordingly, the data wire and the gate pad may be disconnected and/or eroded.